BIOEE 1780 Lecture Notes - Lecture 23: Triploblasty, Synapomorphy, Cephalization
31 Oct 2016
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Division of the body into segments is observed in many animal groups and facilitates: Altering the shape of the body so as to allow more precise control of movement. Adaptive innovations in modes of feeding (predation, filter feeding, herbivory, omnivory) also underlies major adaptive radiations of animals but we will address examples of this as we review major groups throughout the remainder of this lesson module. Synapomorphies: totipotent cells, mineral spicules lack both distinct embryonic cell layers and true organs their basic body plan is an aggregation of cells built around a water canal system. In place of mouths, sponges have tiny pores located in their outer walls through which water is drawn. The flow of water through the sponge is unidirectional, driven by the beating flagella of specialized feeding cells (choanocytes) embedded within the interior of the sponge body. Sponge cells are more independent of each other than are the cells of other animals.
